Both conventional (manual) transmissions and automated mechanical transmissions (AMT's) typically include a simple two-state electrical switch associated with one of the shift rails of the transmission to provide an indication to associated components of the power train or the vehicle operator that the transmission is in neutral. Generally as well, such switches are associated with the engine starting circuitry such that the engine cannot be started unless the switch indicates that the transmission is in neutral. Typically, such switches are configured in a fail safe mode, that is, a normally closed switch provides a signal when the switch is deactivated by alignment with a recess or other feature in the shift rail which allows the switch to relax. When the switch is depressed because the shift rail is out of the neutral position, the switch is open and no signal passes to associated equipment. This configuration fails safe because an open switch, signal or wiring failure will be interpreted as not neutral by the associated power train components which is the safer failure mode. Furthermore, if the switch sticks in the depressed position, once again, the signal provided to associated components will be not neutral which will, for example, disable the engine start capability. This condition or failure mode is safer than a condition in which the transmission is not in neutral but the neutral switch sticks or malfunctions in some manner and indicates that the transmission is in neutral which may permit the engine to be started.
This fail safe configuration of the neutral switch, however, can occasionally create an operational and reliability problem. Simply because the neutral switch sticks in an open or non-neutral position due to aging, cold weather or other random influence, it will not be possible to start the vehicle engine.
Jogging, which is a shift lever action known to most users of manual transmissions, involves transversely moving the shift lever back and forth across the center, transverse portion of the shift pattern. While this action has no functional or operational consequences with regard to shifting the transmission, this is frequently done by a manual transmission operator to confirm that the transmission is in neutral. It has been found that quite frequently a sticking neutral switch can be at least temporarily corrected, i.e., unstuck, by jogging or cycling the shift lever and the associated shift rail.